Gas turbine power plant



April 27, 1 M. H. L. SEIDILLE GAS TURBINE POWER PLANT Original Filed Feb. 28, 1945 INVENT Wit/144 541144111.

# TTOR NEyJ Patented Apr. 27, 1954 UNITED STATES PATENT QFFICE GAS TURBINE POWER PLANT Marcel Henri Louis Sdille, Paris, France, as-

signor to Societc Rateau (Societe Anonymc), Paris, France, a company of France Claims priority, application France March 29, 1941 3 Claims.

In a gas turbine plant operating on liquid or solid fuels, the fuel control is obtained with power losses which represent only a small fraction of the total power. In plants operating on gaseous fuels (blast furnace gas, coke furnace gas, producer gas, etc.) the gas compressor consumes an appreciable power which is a relatively important fraction of the total compression power. It is therefore necessary that the total compression work be effected with the smallest possible power loss at the different power outputs required from and delivered by the plant in order that the overall efficiency oi the system remains good.

This application is a division of the pending application Serial No. 580,257, filed February 28, 1945 (now Patent No. 2,621,476, issued December 16, 1952), which is a division of my prior patent application Serial No. 434,986, filed March 16, 1942 (now Patent No. 2,374,239, issued April 24, 1945).

The present invention has for its object a gas turbine plant operating on a fuel Which is in gaseous form at ordinary temperature, the compression of air necessary to the combustion of this fuel being effected in substantially constant working conditions of maximum efficiency of the air compressor for every power output supplied by the plant.

The invention has for another object a plant of the type defined in which besides the air compression, the gaseous fuel compression is effected with the smallest possible power loss.

Other objects of the invention will be apparent in the following description given by way of example with reference to the drawing in which:

Figures 1 and 2 are diagrammatical views showing various embodiments of the invention.

In the embodiment shown on Fig. l, a motive turbine Tm drives an electric generator K for the supply of useful external power. An auxiliary turbine Ta mechanically separated from the motive turbine Tm and receiving its motive fluid in parallel with same drives a rotary air compressor C which delivers air under pressure into a combustion chamber Ch in which this air is heated before entering the turbines Tm and Ta.

The combustion chamber Ch is supplied with a fuel which is in gaseous form at ordinary temperature. This fuel is compressed in a rotary gas compressor G which is mechanically separated from both turbine Ta and I'm and which is driven by an electric motor M receiving its power from a shunt winding connected to the electric generator K driven by the motive turbine Tm. The regulation of the motor M is effected by means of a rheostat 1'.

It is known that a rotary compressor has a characteristic curve showing a point of maximum efiiciency at a certain speed and for a constant intake pressure, as this is substantially the case for atmospheric air sucked in by the air compressor C'.

It is further known, and this can beshown theoretically, that an auxiliary turbine driving the air compressor and mechanically separated from the motive turbine while supplied with hot air under pressure from a common combustion chamber can always be designed in such a manner corresponding to the point of its characteristic curve at maximum efficiency, the air compressor delivering into the combustion chamber a quantity of air which is suilicient for the combustion of the total fuel supply corresponding to the maximum thermal energy that the motive turbine can transform into useful power.

The regulation of the thermal energy which is to be delivered to the plant is then obtained by means of the rheostat r controlling the motor M which drives the gas compressor G at a more or less great speed according to the quantity of gaseous fuel which is to be supplied to the combustion chamber in order that the motive turbine may deliver the required power output.

In Figure 2, the compression of the combustible gas is effected in two stages connected in series. The low pressure portion of the compression is effected in a blower V coupled with the shaft of the compressor 0. The high pressure portion is effected in a compressor G driven by the motor M controlled as described above.

In this case, the overall eiiicienoy of the plant is increased by the fact that at least a part of the compression work of the gaseous fuel is effected in constant conditions of substantially optimum efiiciency i. e. that the blower V remains nearly in working conditions corresponding to the value of maximum efficiency on its characteristic curve. If the quantity of gas sucked in by the high pressure compressor G varies the pressure at the outlet of the blower V varies but slightly. In this respect, an advantageous arrangement consists in eifecting the low pressure portion of the gas compression in a centrifugal fan and the high pressure portion in a volumetric compressor. The control of the speed of the latter allows for example to reduce the supply with a good efficiency, the low pressure compressor re maining very near to its optimum working condition and the resulting loss being negligible.

In the embodiments shown on the figures, the gas turbine plant is of a definite type. However, the invention applies to all other types of gas turbine plants operating on gaseous fuel, whatever turbine arrangements and groupings are adopted, Whether refrigerating means, regenerators, reheaters, etc. are utilized or not.

What I claim is:

1. In a gas turbine plant, the combination of a motive turbine for delivering useful power; an electric generator driven by said motive turbine; a rotary air compressor for supplying said turbine with air under pressure; a combustion chamber adapted to beat this air before its admission into said turbine by combustion of a gaseous fuel; an auxiliary turbine supplied with hot air under pressur from said combustion chamber said auxiliary turbine being mechanically separated from said motive turbine and be ing adapted to drive said air compressor at a substantially constant rotary speed substantially equal to the value of the operating point or said air compressor at maximum efficiency; at least one rotary compressor mechancially separated from said turbines and adapted to supply said combustion chamber with compressed fuel which is i gaseous form at ordinary temperature; an electric motor adapted to receive elec-- tric current from said generator for driving said gas compressor; and regulating means for said electric motor for controlling the gaseous fuel output sucked in said gas compressor and delivered into said combustion chamber.

2. In a gas turbine plant, the combination of a motive turbine for delivering useful power; an electric generator driven by said motive turbine; a rotary air compressor for supplying said turbine with air unde' pressure; a combustion chamber adapted to heat this air before its admission into said turbine by combustion of a gas eous fuel; a rotary low pressure gas compressor mechanically coupled with said air compressor and adapted to deliver into said combustion chamber compressed fuel which in gaseous form at ordinary temperature; an auxiliary turbine supplied with hot air pressure from said combustion chamber, said auxiliary turbine being mechanically separated from said motive turbine being adapted to drive said air compressor and said low pressure gas compressor at a substantially constant rotary speed substantially Ill equal to the value of the operating point of said compressors at maximum efficiency; a high pressure rotary gas compressor mechanically separated irom said turbines and adapted to further compress the gaseous fuel delivered by said low pressure gas compressor before its admission into said combustion chamber; an electric motor adapted to receive electric current from said generator for driving said high pressure gas compressor; and regulating means for said electric motor for controlling the gaseous fuel output sucked in by said high pressure gas compressor and delivered into said combustion chamber.

3. In a gas turbine plant, the combination of a motive turbine for delivering useful power; an electric generator driven by said motive turbine; a rotary air compressor for supplying said turbine with air under pressure; a combustion chamber adapted to heat this air before its admission into said turbine by comb-ust on or a gaseous fuel; a rotary low pressure centrifugal fan mechanically coupled with said air compressor and adapted to deliver into said combustion chamber compressed fuel which is in gaseous form at ordi nary temperature; an auxiliary turbine supplied With hot under pressure from sai combustion chamber said auxiliary turbine being mechanically separated from said motive turbine and being adapted to drive air compressor and said centrifugal fan at a substantially constant rotary speed substantially equal to the value of the operating point or said air compressor and of said centrifugal fan at maximum efiiciency; a volumetric rot ry gas compressor mechanically separated from said turbines and adapted to further compress the gaseous fuel delivered by said centrifugal fan before its admission into said combustionchamber; an electric motor adapted to receive electric current from said generator for driving said volumetric gas compressor; and regulating means for said electric motor output sucked in by said volumetric gas compressor and delivered into said combustion chamher.

teiereilces Cited in the file of this patent UNITED STATES PATENTS Nuinb-er Date 1,978,837 Forsling Got. 39, 1934 2,193,114 Seippel Mar. 1940 2,263,705 Seippel r- Nov. 25, 1941 2,303,381 New I cc. 1, 1942 2,374,239 S'dille Apr. 24, 1945 2,621,476 Sdille Dec. 16, 1952 for controlling the gaseous fuel 

